HERF Data #3 - Assassination Science

Likewise, the DO-160C associated results are dominated by one or two emitters in each category.
If these emitters (e.g., a mobile AN/MPN14 in Denver and an AN/SPY-1 emitter in Seattle) are
not actually in fulltime use or have significantly different operating characteristics than those
used in this study, the corresponding probabilities could drop by one or two orders of magnitude.
The DO-160B associated probabilities, however, are much less likely to suffer from aircraft or
emitter position errors or even from particular emitter characteristics. This is because these
relatively low levels are exceeded for many emitters on each flight, a single aircraft position, or a
single emitter.
REVIEW
A study has been completed to assess the risk of HIRF for transport and nontransport (fixedwing)
aircraft in the U.S. The approach to the assessment incorporated:
• detailed information on emitters and flights near two major cities
- A total of 5913 flights of transport category aircraft involving a takeoff or landing
in either the Denver or Seattle area were examined. A total of 893 emitters
ranging in frequency from 500 kHz to 40 GHz were used, with some reasonable
assumptions, to calculate electromagnetic field strengths at aircraft positions.
• quantitative judgments based on industry experience with aircraft and avionics
- Dave Walen of the FAA and Richard Hess of Honeywell Flight Systems acted as
resources with regard to the types of avionics on aircraft, their properties and the
probabilities of different kinds of responses.
• HIRF environment levels from regulatory and standards sources
- The probability of a catastrophic aircraft event was estimated for three different
HIRF threat levels:
1. DO-160B-derived field strengths
2. DO-160C-derived field strengths
3. NPRM certification field strengths
No reliable evidence was found to suggest that flights in the Denver and Seattle areas experience
electromagnetic fields in excess of the NPRM certification levels. Worst case upper limits are
estimated at ~2e-6 and ~1e-5 for transport and nontransport category aircraft, respectively. DO-
160C associated HIRF catastrophic event probabilities are one to two orders of magnitude larger
and DO-160B probabilities are three to four orders of magnitude larger than these pessimistic
upper limits.
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